Lionel Messi played a starring role as Paris Saint-Germain defeated RB Leipzig 3-2 at the Parc des Princes.
PSG, who were without Neymar, took the lead on nine minutes courtesy of a strike from Kylian Mbappe but that didn't last too long as Andre Silva levelled for the visitors in the 28th minute.
Nordi Mukiele then put the visitors ahead, before Messi took over in the final 30 minutes by equalising on 67 minutes before he sealed the winner with a panenka penalty in the 74th minute.
Messi could have had a hat-trick late on after PSG were awarded a penalty but he gave the chance to Mbappe, who was unable to convert.
Liverpool made it three wins from three matches in Group B with a 3-2 triumph over Atletico Madrid in the Spanish capital.
The hosts took the lead on eight minutes when James Milner got the slightest of touches on Mohamed Salah's shot, before Naby Keita doubled the lead on 13 minutes with a superb volley.
The fiery first half continued as Antoine Griezmann pulled one back in the 20th minute before the French striker equalised with a neat finish on 33 minutes.
Griezmann went from hero to villain in the 52nd minute when he was shown a straight red card for a dangerous challenge on Roberto Firmino.
Salah then put the Reds in front on 78 minutes from the penalty spot after Hermoso's clumsy foul on Diogo Jota.
FC Porto bounced back from the loss to Liverpool with a 1-0 triumph over AC Milan.
Luis Diaz got the game's only goal in the 65th minute with a clinical strike from close range.
Ajax Amsterdam continued their fine start in Group C after thrashing Borussia Dortmund 4-0 at the Johan Cruijff Arena.
The Dutch giants raced into a two-goal lead inside 25 minutes thanks to a Marco Reus own goal and a strike from Daley Blind.
Antony added a third goal just before the hour mark before Sebastien Haller rounded off the scoring in the 76th minute.
Real Madrid bounced back from their shock defeat to Sheriff after defeating Shakhtar Donetsk in Ukraine.
Serhiy Kryvtsov gifted Los Blancos the lead with an own goal, before Vinicius Junior bagged to a brace to make it 3-0.
Rodrygo's strike made it 4-0 in the 64th minute while Karim Benzema wrapped up proceedings in the 90th minute.
Inter Milan got their first win in Group D after humbling new boys Sheriff at the San Siro.
Edin Dzeko, Arturo Vial and Stefan de Vrij were on target to seal the spoils for the Serie A champions, while Sebastien Thill bagged the consolation for the visitors.
